Highly sensitive and specific HPLC with fluorometric detection for determination of plasma epinephrine and norepinephrine applied to kinetic studies in humans

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 41; no. 10; p. 1455
• Main Authors: Willemsen, J J, Ross, H A, Jacobs, M C, Lenders, J W, Thien, T, Swinkels, L M, Benraad, T J
• Format: Journal Article
• Language: English
• Published: England 01-10-1995
• Subjects: Adult; Arteries; Chromatography, High Pressure Liquid - methods; Chromatography, High Pressure Liquid - statistics & numerical data; Dopamine - blood; Epinephrine - blood; Humans; Isoproterenol - blood; Kinetics; Norepinephrine - blood; Sensitivity and Specificity; Tritium; Veins
• ISSN: 0009-9147
• DOI: 10.1093/clinchem/41.10.1455

An HPLC separation method combined with fluorometric detection was extended to enable simultaneous assessment of plasma 3H-labeled and endogenous epinephrine (E) and norepinephrine (NE). Forearm fractional extraction (FFE) of 3H-labeled E and NE and of endogenous E was measured in 40 healthy volunteers who were receiving a continuous infusion of 3H-labeled E and NE. Concentrations of arterial and venous E were 26.8 +/- 1.95 (mean +/- SE) and 6.8 +/- 0.75 ng/L, respectively. Arterial and venous NE and dopamine (DA) were also measured, with respective values of 140.7 +/- 8.5 and 192.1 +/- 15.1 for NE, and 13.1 +/- 0.78 and 11.3 +/- 0.70 ng/L for DA. The FFE of 3H-labeled E was slightly but significantly higher (0.790 +/- 0.016) than the that of either 3H-labeled NE or endogenous E (0.748 +/- 0.0146 and 0.745 +/- 0.0185, respectively; P < 0.001), the correlations being highly significant (r = 0.80, P < 0.001) in both cases. The small difference between the FFE of E and of 3H-labeled E allows the calculation of the apparent spillover of E. However, this spillover was negligible compared with forearm NE spillover (0.0112 +/- 0.0031 vs 1.369 +/- 0.128 ng/L per minute. The high sensitivity of this measurement of venous E widens the possibilities for studying E kinetics under physiological conditions.